Timeline of the Past

The Earth was created after the Sun due to accretion of leftover particles and debris. The formation of the Earth was only the beginning and we still see the Earth changing year by years through erosion and plate tectonics. However in learning more about the formation of the Earth we are able to better understand what makes life possible on our planet.

A ribozyme is an RNA molecule that is capable of catalyzing specific biochemical reactions, similar to the action of protein enzymes. Some ribozymes may play an important role as therapeutic agents, as enzymes which target defined RNA sequences for cleavage, as biosensors, and for applications in functional genomics and gene discovery.

Early atmosphere formed 4.1 BCE consisted of mainly hydrogen.
Second atmosphere formed 3.4 BCE was due to outgassing from volcanoes, Earth’s second atmosphere consisted mainly of nitrogen and carbon dioxide.
a. First use of H20 as source of hydrogen 3 BCE was significant because water was first used as a source of hydrogen.It takes two molecules of the diatomic hydrogen gas, combined with one molecule of the diatomic oxygen gas to produce two molecules of water. In other words the ratio of hydrogen to oxygen is 2:1, the ratio of hydrogen to water is 1:1, and the ratio of oxygen to water is 1:2.

Protobionts evolve from primitive life. They exhibit some of the properties associated with life, including simple reproduction, metabolism and excitability, as well as the maintenance of an internal chemical environment different from that of their surroundings. It has been suggested that they are a key step in the origin of life on earth.
Lysosomes are organelles that contains digestive enzymes (acid hydrolases). They digest excess or worn out organelles, food particles, and engulfed viruses or bacteria. The membrane surrounding a lysosome prevents the digestive enzymes inside from destroying the cell. Lysosomes fuse with vacuoles and dispense their enzymes into the vacuoles, digesting their contents.

Organisms start using photosynthesis to gather energy from the sun. Photosynthesis is the conversion of light energy to chemical energy by living organisms such as plants. It is essential for a number of reasons primarily because one of the raw materials is carbon dioxide which is harmful in high concentration to humans and most other aerobic (oxygen breathing) organisms. One of the "waste" products of photosynthesis is oxygen which is vital for most life-forms on earth including humans.

Prokaryotes are based on what these organisms are not (they are not eukaryotic), rather than what they are (either archaea or bacteria).The differences are that ribosomes in prokaryotes are smaller than in eukaryotes. However, two organelles found in many eukaryotic cells, mitochondria and chloroplasts, contain ribosomes similar in size and makeup to those found in prokaryotes. This is one of many pieces of evidence that mitochondria and chloroplasts are themselves descended from free-living bacteria.

Endosymbiosis explains the origin of mitochondria and chloroplasts. Their origins have been suggested for many structures, including flagella (structures like the tail of a sperm), cilia (hair-like structures that help in locomotion), and even the nucleus — the cell's command center.
Process formed an interconnected tree of life in which organisms have multiple ancestors, even from different domains. As eukaryotes, our ancestors include both the bacteria that became mitochondria, and the archaebacterium that was the host cell.

Prokaryotes do not have a membrane bound nucleus, mitochondria, or any other membrane-bound organelles. In other words, all their intracellular water-soluble components (proteins, DNA and metabolites) are located together in the same volume enclosed by the cell membrane, rather than in separate cellular compartments. Most prokaryotes are unicellular organisms.

Oxygen is one of the most important elements required to sustain life. Without it, our health begins to suffer and/or we die. Unhealthy or weak cells due to improper metabolism lose their natural immunity and are thus susceptible to viruses and lead the way to all kinds of serious health problems. It gives us life but destroys also the harmful bacteria in our bodies without affecting the beneficial bacteria that we need.

Eukaryotic cells may contain several other types of organelles, which may include mitochondria, chloroplasts, the endoplasmic reticulum, the Golgi apparatus, and lysosomes. Each of these organelles performs a specific function critical to the cell's survival. Moreover, nearly all eukaryotic organelles are separated from the rest of the cellular space by a membrane, in much the same way that interior walls separate the rooms in a house. The membranes that surround eukaryotic organelles are based on lipid bilayers that are similar (but not identical) to the cell's outer membrane. Together, the total area of a cell's internal membranes far exceeds that of its plasma membrane.